I have:
- Magisk (26.1) with zygisk enabled
- Zygisk - LSposed v1.8.6 (6712) installed and enabled in Magisk
- MinMinGuard 2.2.0 ('fixed' version from xda) installed and enabled in LSposed for all apps via hide uncheck everything and then active for every app I have (you can just activate for the app you want to test with, but ymmv, maybe it uses a system app to get the ads)
- in MinMinGuard I've used the whitelist option with 2 games activated in the list as I want to have ads there to get more goodies
It could be the version you use. I totally forgot I had a 'fixed' version for Android 11+ (it's been running almost a year without issues/ads getting trough).